Let's start by breaking down the five things you'll notice most in moving from the Nexus 4 to the Nexus 5:

1. Display

The Nexus 5's 4.95-in. 1080p display looks fantastic and is a significant step up from the 4.7-in. 720p screen on last year's device. The N5's display is brighter with crisper detail, more brilliant colors and more pure whites. The Nexus 4's display looks dull and washed out in comparison. Personally, if any one thing were to convince me to upgrade, the screen would probably be it.

This'll matter more to some folks than others, but the Nexus 5 supports LTE on all major U.S. carriers except Verizon (no surprise there). If you're among the crowd that lamented the Nexus 4's lack of LTE, well, there ya go.

4. Local storage capacity

Nexus phones are likely never going to be local storage monsters, but the N5 comes with the option of 32GB -- double the N4's max capacity.

5. Design and style

The best way to describe the new Nexus is less premium but more comfortable than its predecessor. The phone's soft-touch rubberized plastic casing is nice to hold and presumably less fragile than the N4's glass, but the device is definitely less distinctive-looking and also somewhat less thoughtfully designed. All in all, it's kind of a wash; which body is better largely comes down to personal preference.

All considered, I'd say this: The LG-made Nexus 5 is a nice step up from the also-LG-made Nexus 4 -- but it's really not a life-altering leap. If you have the cash to spend and are itching for something new, the Nexus 5 is an upgrade you'll enjoy. If any of the aforementioned areas are important to you and you're looking to stay within the Nexus line, the new phone is a no-brainer.

The Nexus 4 still performs like a champ, though, and will soon get the parts of KitKat that really matter. Unless you're just jonesing for an upgrade, you'd probably be fine to stick it out with the N4 a while longer and wait to see what comes along in 2014.